irfpy.cena.intersection

Calculate the CENA FoV cross-section on the Moon’s map

irfpy.cena.intersection.get_center_me(t, dir, as_vector=False)[source]

Get the intersection between the given pixel and the surface.

Returns the intersection between the given pixel dir and the lunar surface. ME frame is used.

Parameters

  • t (datetime.datetime) – Time in datetime.datetime instance.

  • dir (int) – Direction number. 0 to 6.

  • as_vector (boolean) – If True, return as a vector in ME frame.

Returns

If as_vector is True, the numpy.array instance with (x, y, z) is returned. Otherwise (default), A list of [longitude (deg), latitude (deg)] will be returned.

Note that the Moon is assumed to be a sphere with 1738 km radius here. This is just a geometric vector calculation, and no SPICE is used.

>>> t = datetime.datetime(2009, 1, 31, 3, 25, 17)
>>> lon, lat = get_center_me(t, 4)
>>> print('%.1f' % lon)
69.9
>>> print('%.1f' % lat)
62.5

>>> lon, lat = get_center_me(t, 0)
>>> print('%.1f' % lon)
85.1
>>> print('%.1f' % lat)
62.3

>>> lon, lat = get_center_me(t, 6)
>>> print('%.1f' % lon)
59.8
>>> print('%.1f' % lat)
62.2
irfpy.cena.intersection.in_cena_fov(t, me_lon, me_lat)[source]

Return if the given position is in CENA’s FOV or not

Parameters

  • t – Time

  • me_lon – Longitude of surface position, deg

  • me_lat – Latitude of surface position, deg

Returns

True if (me_lon, me_lat) is in CENA’f FOV

>>> print(in_cena_fov(datetime.datetime(2009, 4, 15, 2, 22, 59), 177.5, -45.5))   # False
False
>>> print(in_cena_fov(datetime.datetime(2009, 4, 15, 2, 26, 19), 177.5, -45.5))   # True
True